Why The Drought Is nearly Gone

 

More evidence that the Australian drought is nearly over can be found by looking at the timing of past droughts, and identifying a pattern.  It will come as no surprise that all of them have appeared around El Nino years, because talk of El Nino usually comes about after the dry sets in.  But it may put a different twist on the matter if El Nino is identified as a sequential pattern that can be used to extrapolate both into the distant past for which records are unavailable and into future years not yet come.

 

The signature of an El Nino is warmer water off the west of South America with heavy rain and floods there and corresponding cooler water off Australia leading to drought.  An El Nino is the result of changes in the air pressure across the southern Pacific Ocean, known as the southern oscillation index.  Changes in air pressure are brought about monthly by the Moon changing hemispheres due to the 23deg tilt of the earth, and every 18-19 years a maximum north and south latitude is reached in this cycle bringing peaks to the air pressure change system which results in a regime cycle in temperatures.

 

Perhaps weather experts are too busy looking at ocean temperatures as measured by buoys.  There is a belief that sea temperatures heat the air and then drive the air pressure in a closed system.  However it is not a closed system and the air above the sea heats the surface of the sea and not vice versa.  The air temperature is driven by the heat from the sun and distributed from the tropics by the Moon.  .

 

It does not take much analysis of data to see the pattern is evident and it is robust.  The drought of 1901-2 was called an El Nino year, as were the years 1913-14, 1918-20, 1935-36, 1940, 1943-44, 1951, 1965-68, 1972-73, 1982-83, 1991-95 and 1996 onwards.  These have been the main Australian drought-defined periods of the last century.  Equivalent dry years in the previous century would have been 1807, 1825, 1843, 1888.  Unfortunately Sydney data goes back only to 1858, and Sydney received only about half the average rainfall in 1888 (583mm) which fits the pattern.

 

Between 1900 and 2006 a total of 11 identified El Ninos have occurred in 106 years, averaging 9.5 years between each.  Droughts occur in the same place every 9-11 years.  This is a combination of the lunar cycle of 9 years and the sunspot cycle of 11 years.  These gaps are not exact and may vary over a shorter term, but over a longer term the average gap closely adheres to this figure.

 

Let's look at a few gap years between dry periods.  Droughts were during 1963-68 then 1972-73, showing a 9 yr gap between 1963-1972.  The next drought was 1982-83.  It is 9 yrs between 1973-1982.  Then we had the drought of 1991-95.  It is 9 years between 1982-1991.  After that we have drought kicking in around 2005.  It is 10 years between 1995-2005.  9 years is a multiple of 18 and 36, which are lunar cycles.  From this, we can predict that the next El Nino and Australian drought period of significance may click in around 2011-12.

 

Rainfall figures spanning 1938-2005 for Glenprairie, QSLD, have been sent to me.  Low rain years there fit in very well to the El Nino pattern.  They were 1938 (504mm), 1944/45 (531mm), 1952 (461mm), 1957 (361mm), 1965/66 (336mm), 1972 (476mm), 1977, 1982 (375mm), 1987 (503mm), 1992/93 (451mm), 1997 (438mm), 2002 (345mm), 2006 (453mm).  The gap numbers between these years are roughly 6, 7, 5, 8, 7, 5, 5, 5, 5, 5, 5, 5.  Droughts are plottable near maximum lunar declinations, because high maximum temperatures become more extreme with the moon's more northern latitude.  Mostly, the years following lunar maximum declinations have been wetter than average and we can look to them for years of rain relief.  These years have been have been 1804, 1840, 1858, 1899, 1915, 1933, 1951, 1971, 1989, 2007, and perhaps will be 2026.  Again Glenprairie still shows a clear trend, for example heavier-than-average rain years were 1951 with 1187 (mm), 1971 (1340mm), and 1990 (1076mm).

 

So drought-hit farmers can take heart. They may have passed the worst of it.

 

© Ken Ring